The present disclosure is a continuation of earlier applications titled “Multi-spectrum Photosensitive Device and Manufacturing Methods Thereof” (PCT/CN2007/071262) and “Multi-spectrum Photosensitive Device and Manufacturing Method Thereof” (Chinese Application No. 200810217270.2) owned by the present inventor, and aims to provide more specific and preferred semiconductor physical implementations.
The previous sensing devices focus on sensing either color visible light or infrared light, few of them sense both of color visible light and infrared light. Although there are other inventions or applications, such as using indium antimony semiconductor technology (“Silicon infrared focal plane arrays”, M. Kimata, in Handbook of Infrared Detection Technologies, edited by M. Henini and M. Razeghi, pp. 352-392, Elsevier Science Ltd., 2002), to simultaneously realize photosensitivity of visible light and infrared light, they do not sense color of light. The existing method of simultaneously obtaining the color and infrared light is to physically superpose a color sensing device with an infrared sensing device (such as “Backside-hybrid Photo detector for trans-chip detection of NIR light”, by T. Tokudaetal, in IEEE Workshop on Charge-coupled Devices & Advanced Image Sensors, Elmau, Germany, May 2003, and “A CMOS image sensor with eye-safe detection function using backside carrier injection”, T. Tokudaetal, J. Inst. Image Information & Television Eng., 60(3):366-372, March 2006).
There are three main reasons for failure of the existing sensing device in integrating the color sensing device with infrared sensing device. The first reason is that the existing color sensing device needs to use color filter film (including red/green/blue, or cyan/yellow/magenta/green) to get the color. However, these filter films also have a strong filtering characteristic on the infrared light. In addition, in order to make color vivid, an infrared filter is added to the lens specifically to reduce the possible fogging phenomenon caused by infrared light on color image. Foveon Company's X3 three-layer sensing technology achieves the selection of color according to the depth. Though this method does not use the filter film, the manufacture of the three-layer sensing technology has been very difficult and industrialization is not very successful. If an infrared layer is further added below the three layers, it will be more complicated and there is almost no practical value. The second reason is that silicon that is widely used in semiconductors absorbs the infrared with wavelength only below 1100 nm. Therefore, many infrared sensing devices utilize other semiconductor materials, such as germanium, silicon-germanium mixed crystals, HgCdTe, InSb and the like. These materials are not suitable for sensing visible light. The third reason is due to lack of practicable technology for manufacturing double-layer or multi-layer sensing device.
Therefore, some problems, such as how to achieve better photosensitivity and integrate the color sensing device with infrared sensing device, needs to be further invented and improved.